Alternators are rotating electrical generators converting mechanical energy from the engine’s crankshaft into electrical energy. Typically engine-mounted and belt-driven, they supply power for vehicle electrical systems and recharge the battery. Output is regulated via an internal voltage regulator to maintain a consistent voltage, typically 13.5-14.5V. Core components include the rotor, stator, rectifier diodes, and regulator, all housed within a sealed unit. Modern alternators frequently utilize a serpentine belt drive and may incorporate one-wire or high-output modifications for specialized applications.